Data-backed planning intelligence · 3,780,000+ decisions analysed across England

Rear Extension Approval Rates in East Hertfordshire

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 5,401 real decisions tell us about rear extension outcomes in East Hertfordshire.

5,401 real decisions·January 2020 to August 2026·Updated August 2026
78.8%
Approval Rate
5,401
Decisions
4,256
Approved
1,145
Refused
78.8% approved. But 1,145 refused since 2020. Each refusal cost the homeowner time and money on drawings and application fees. Understanding your local data before you apply is the difference between confidence and a costly gamble.

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Why rear extension approval rates matter

Rear extensions sit in the middle of the pack nationally. They're common enough that councils have clear precedent — but that cuts both ways. If your neighbours have been refused, that precedent works against you too.

These are council averages. Your property is specific.

Two houses on the same street can get different outcomes.
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How rear extensions compare to other project types

Not all applications are treated equally. Here's how rear extensions stack up against other common projects in East Hertfordshire.

TypeDecisionsRate
Conservatory1,063
82.8%
Rear Extension5,401
78.8%
Wraparound Extension535
78.3%
Extension (General)693
75.5%
Loft Conversion972
75.4%
Front Extension1,069
75.0%
Outbuilding1,446
74.5%
Side Extension3,038
74.2%
Dormer1,676
73.9%
Basement234
72.6%
Garage / Parking4,325
71.3%
Hip-to-Gable Conversion223
70.9%
HMO20
70.0%
Annex352
63.9%
Flat Conversion41
63.4%
Change of Use (Residential)1,050
62.9%
New Build1,299
62.5%
See how this applies to your postcode →

What the data tells us

1
78.8% of rear extension applications in East Hertfordshire get approved. That means 1,145 homeowners since 2020 have been refused. Not terrible odds, but not a foregone conclusion.
3
Council averages are starting points, not guarantees. The decisions that matter most are the comparable ones near your specific property — because planning officers look at precedent, character and the immediate context of your street.

Before you spend £5,000+ on architects and drawings

1,145 rear extension applications in East Hertfordshire have been refused since 2020. Many of those homeowners had already paid for drawings and application fees. A free, property-specific report shows you what gets approved — and what gets refused — near your property.

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Free · Property report emailed in minutes · Based on 3,780,000+ real decisions

More East Hertfordshire planning data

Nearby councils rear extension data

Methodology: Based on 5,401 planning decisions classified as rear extensions in East Hertfordshire, January 2020 to August 2026. Classification uses keyword matching against proposal descriptions (matching generate_site_data.py rules). A single application may appear in multiple categories. Approval rate = approved / (approved + refused). Pending, withdrawn and invalid applications excluded. Data from East Hertfordshire Council's public planning portal. Full methodology →
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